1. Field of the Invention
The present invention relates to a rotary knob structure provided at a device body, and particularly relates to a rotational structure configured to provide rotational resistance to a rotary knob.
2. Description of the Related Art
For example, a rotary knob is attached to a body of, e.g., an audio device to perform various types of operation. Some of these rotary knobs are configured to provide a weighted operational feeling in such a manner that rotational resistance is provided while the rotary knob is rotating.
For example, JP-A-2010-257711 discloses a rotational structure for a rotary knob. In the rotational structure, an annular spacer as a stack of an elastic member and a sliding member is interposed in a clearance between a device body and the rotary knob. The annular spacer slides on the rotary knob to provide rotational resistance to the rotary knob. As a result, backlash of the rotary knob is reduced.
However, in the rotary knob rotational structure as disclosed in JP-A-2010-257711, the annular spacer is tightly interposed in the clearance between the device body and the rotary knob. For this reason, when the size of the clearance changes due to an influence such as variation in the dimensions of the rotary knob, the magnitude of rotational resistance also changes. Thus, it is difficult to provide a suitable magnitude of rotational resistance to the rotary knob.